1592 



RUSSELIA 



EUSSfiLIA (Alexander Russell, Eiitrlish physician 

 and author of "Natural History of Aleppo," ISSO). 

 ScrophuJarnu-eii'. About a dozeu species of Mexican 

 shrubby plants with angular, usually slender, often 

 pendulous branches: Ivs. usually small, becoming scale- 

 like on the branches, opposite or verlirillatc : tls. liriglit 

 red, in dense or loose corymbs or of a single flower; 

 calyx .5-parted; corolla - tube cylindrical, the lobes 

 spreading and nearly equal; staminodia Tery short or 

 wanting; stamens i: capsule subglobose, 2-celled : 

 seeds iuimer<ius. very small, winged. A recent syno]i- 

 sis of Russelia by Dr'. B. L. Robiiiscm, with a key to the 

 species, will be found in Proc. Am. Acad. Arts A: Sci., 

 vol. 35, No. IG, March, 1900, 



Russelias are of easy cultivaticm. ii'. j»»(C(i and its 

 varieties make excellent basket jdants, boing almost 

 continuously in bloom. Propagated by cuttings. 

 .\. Pr (hi tides l-J-fhiiririiJ. 



jiincea, Zurc { I,\ .■^■'■iiniUi. Hort.l. (.'oral Plant. 

 Fig. 2220. A tcmb-r shrubby plant, witli smooth, somewhat 

 rushdike branches, nodding or pendulous at the to|i: 

 Ivs. lineardanccolate or ovate, small, becoming jninute 

 bracts on the branches: racenu- very loose, remotely 

 flowered: peduiudes elongat.-d. B.R. 21:1/73, P.M. 4:79, 

 — Vars. Lemoinei anil elegantissima are garden hybrids 

 of 7?. jiiiirrii and 7i'. .•iiiriiientosii . They are more florif- 

 eruus, especially during the winter, than the type. 

 AA. Pi iJitiicleK w(t iiii-fUiirared. 



sarmentosa, Jacq. (77. ninlllfliiru . Sims). A tender 

 shrub, becoming 4-0 ft. high: Ivs. <jpp"site, ovate, acu- 

 minate, serratelv .'rFnate: tls. verlicillate, many in a 

 terminal raceme.' B.M. 152S. P.M. 10:l(;:i. R.H. 1852:281. 



P. W. Baeulav. 



RUSSIAN CACTUS. Same as Russian Thistle. 



RUSSIAN FRUITS. See P.niiuhuiii . R, THISTLE, 



See Salsolii. 



RUST. Anime foi a class of fungi which produce 

 disease m plants Rusts are of the class Uredine*. 

 The mjfchum bi in( hi s aniong the tissues of the host 

 and piodm Hs se\eial kinds of spores, either uiion 

 the one host (.into < inns I ii upon different hosts 

 (hetercecn)U^l Thi sc spoies is shown typically in the 

 disease of tlit win d .ti( < illed n spcctively uredospores, 

 teleutosp»on s a < idiospuies i ti Recent researches b>" 

 Eriksson lud H< nnmg m S"\\etlen show that the three 

 common rusts \\hii h ittei t tht grains, namely : Piiecitiia 

 Hru)niiii\ (Pigs 2^21-2}, P I ifbii/o-fefii and P. coroiiidii. 

 (•■An be spilt up into seven species, characterized by 

 their cultural rear tions with a large .series of plants, and 

 that Pun una i/iiniinii\ has he.sicle.s six specialized 



2221. 

 Colonies of Rust 

 on the stem of 

 wheat. 



2222, 

 The cluster - cud 

 stage of the 

 wheat Rustfun- 

 e;us Ernwing on 

 a barberry leaf. 



forms, delimiteil by differences in the marked cai>acity 

 of the uredo- or teleutospores to inoculate on ditTcrent 

 hosts. Several rusts are common on cultivated plants, 

 causing disease; viz., beet rust ( rnniuii-e.i 73i7ic), broad 

 bea,n rust { rnnuilr: x Fulin). white pine rust {('roii' 

 art in III r'tbinihnu I . asparagus rust ( Purr 'mi a Aspunuii) , 



RYE 



chrysanthemum rust {Purriniu Hieracii), black, or 

 wheat rust (Piicrhiiu i/rumiiiixj, hollyhock rust {Pne- 

 ciiiiu nialvacearuitt ), etc. .John W. Harshbekcer. 



The rusts are fungi constituting a very large and 

 economically important class known as Urediuefe. 

 They are all" obligatory parasites, attacking a vast num- 

 ber of native and cultivated )ibints. The mycelium of 



2223. Ruta graveolens. Fkiwers slightly enlarged. 



the rust fungi exists entirely -witliin the tissues of the 

 host. The spores are formed in masses or sori just be- 

 neath the epidermis. When ripe they break through 

 the epidermis, forming brown patches and spots from 

 \\'hich they are scattered. Many of the rusts produce 

 several spore-forms, which often occur in regular succes- 

 sion either on the same host or on diiferent hosts. For 

 example, the \ybeat rust pi reduces uredospores and teleu- 

 tospores on the wheat and airidiosiiores on the barberry. 



Rusts rarely kill the plants which they affect, and 

 hence in many cases the damage done is not as appar- 

 ent as in many other diseases. In all cases, however, 

 the pdants are weakened, and often much disfigured, 

 The}^ are among the most difficult fungous diseases to 

 combat, Sv>raying has been tried in many instances, 

 but has proved, at mcist. only partially successful. The 

 most prohtable course for oycrcoming these diseases 

 seems to Ije the selection of resistant varieties. 



IIeinkich Hasseleeing. 



RtTTA (chissical name of rue). Putacece. About 40 

 sjiecies from the Mediterranean region of Europe and 

 from Asia. Perennial herb.s, often woody at the base, 

 glandular, punctate: Ivs. simple to much pinnate, odor- 

 ous : tls. yellow or greenish, in terminal corymbs or 

 yianicles, herniaphroditc. usually 4-inerous; petals 4-5, 

 free, often dentate orciliate; si:iniens 8-10: ovary ses- 

 sile: capsule 4-5-lolie<l. indeliisi'cnt or dehiscent at apex. 



graveoleus, Linn. Rue, Hkkb op Grace, Fig. 222!!. 

 A hardy perennial, woody at the base, lK-2 ft. high : Ivs. 

 fragrant, nimdi divideil; lobes oblong, the terminal ob- 

 ovate: fls. ycdiow. .luly. Pro|i. by divisiim and seeds. 



Patavina, Linn, i TTaiiluiilii'illiiiu Pnlu r'liiiu . Hort.). 

 A harily perennial herb 4-0 in. high: Ivs. glalu-ous, the 

 lower oblongspatulate, narrowed at the base, the others 

 trisecded and laciniate: c<"tr\'mb dense; pedii-els some- 

 what longer than the fls. : fls! golden yellow. June,, luly. 



F. W. Bakceav. 



RUTABAGA, or SWEDISH TURNIP. Consult Brus- 

 .s;c(( ruiuiirsd'i.^, page 177; also Turnip. 



RUTLAND BEAUTY is Cniimlriilux Stpiiiiii. 



RYE. See ^Vrr//,'. RYE, Wild. »ee Jih/iiius. 



